Transformer tap for underground applications with pressure plate connection



Oct. 13, 1970 5 BECKER ETAL 3,534,323

' TRANSFORMER TAP FUR UNDERGRQUND APPLICATIONS WITH PRESSURE PLATE CONNECTION Filed March 6, 1969 2 Sheets-Sheet 1 I FIG. 2

Y INVENTORS STEP/lily P. BA'CAE? l/E/VRY )3. Wf/VGE IV ATTO R N EYS Oct. 13, 1970 s, p, BEcKER EI'AL 3,534,323

* TRANSFORMER TAP FOR UNDERGROUND APPLICATIONS WITH PRESSURE PLATE CONNECTION 2 Sheets-Sheet 2 Filed March 6, 1969 INVENTORS STEPHEN r? BECAIR HENRY R. W/Y6/V BY v ATTORNEYS United States Patent 3,534,323 TRANSFORMER TAP FOR UNDERGROUND APPLICATIONS WITH PRESSURE PLATE CONNECTION Stephen P. Becker and Henry R. Wengen, Poughkeepsie,

N.Y., assignors to Fargo Mfg. Company, Inc., Poughkeepsie, N.Y., a corporation of New York Filed Mar. 6, 1969, Ser. No. 804,856 Int. Cl. H01r 3/02 US. Cl. 339-116 6 Claims ABSTRACT OF THE DISCLOSURE A rugged and compact connector or tap to a transformer or other encased electrical components for direct burial applications providing permanent, water-tight, insulated junction including internal and external attachment means and external insulation means and also including pressure plate means for positively fastening a conductor thereto from the direction opposite to that of conductor insertion.

BACKGROUND OF THE INVENTION It has become highly desirable for a number of reasons to bury electrical components, such as transformers, underground. Connector assemblies, or taps, for such underground applications must be specifically designed with this end use in view. In direct burial applications where the connection to the transformer is made and left without benefit of enclosure in a vault, the tap or connection means used must be moisture-proof and provide its own sealing. Additionally, it must be relatively simple to use. In certain applications the fastening of the con- 3 ductor through the tap is made from the same direction as that in which the conductor is inserted. In certain applications it has been found desirable to provide means for fastening the conductor to the tap from the direction opposite to that of conductor insertion. Suitable means for making a positive connection from the direction opposite to that of conductor insertion have not been provided by the prior art transformer tap or connection means.

SUMMARY OF THE INVENTION A transformer tap including a stud member projecting through the transformer cover with first and second portions disposed internally and externally of the transformer cover, internal and external cover fastening means supported by the stud member, internal and external insulation means between the cover and the respective internal and external fastening means, external conductor attaching means and first and second sealing means for respectively providing sealing between the conductor attaching means and the conductor and the conductor attaching means and the external cover fastening means, and a pressure plate accessible from the direction opposite to that of conductor insertion whereby a positive connection of conductor can be made from the direction opposite to that of conductor insertion.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings,

FIG. 1 is a longitudinal sectional view of a transformer tap assembly constructed in accordance with the teachings of this invention;

FIG. 2 is an exploded segmentary perspective view of the pressure plate and body member which is utilized for cable attachment; and

FIG. 3 is an exploded perspective view of that portion 3,534,323 Patented Oct. 13, 1970 of the assembly shown in FIG. 1 which is utilized for cable attachment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the figures, the transformer cover or side wall is indicated by the numeral 10. A stud member 12 projects through an opening in the cover 10 and supports internal and external cover fastening members 14 and 16, respectively. The stud is formed of conducting material, such as copper, and the fastening members are formed of nonconducting material, such as porcelain. The external cover fastening member 16 has a portion 16a projecting through the opening in cover 10 and disposed within bore 14a of internal cover fastening member 14. Insulating baskets 18 and 20 are respectively supported between internal member 14 and cover 10 and external member 16 and cover 10.

Internally the internal cover fastening member 14 is held against the gasket 18 by fiat washer 22 and jam nut 24. These are mounted on threaded end 12a of stud 12. Jam nuts 26 and 28 are also supported on threaded end 12a to maintain flat washers 30 and 32 between jam nut 28 and 24. The internal connection of the transformer winding is made to the tap by disposing the winding end between flat washers 30 and 32.

The remaining ends of stud 12 which is also threaded at portion 12b is threaded within cavity 34a of conducting body member 34 to clamp external cover fastening member 16 and gasket 20 against cover 10. Gasket 36 also constructed of insulating material is disposed betweenthe cover fastening member 16 and body member 34.

The external cover fastening member 36 and the member 34 are provided with an insulating coating 38 such as durable hard vinyl by means of a dip coating process. Of course, other insulating materials can be used for coating or enclosing the fastening member 16 and body member 34 and other means of attachment of the insulating material to these members can be utilized in the practice of the invention.

The body member 34 is provided with a cylindrical bore section 340 and a conical bore section 34b. Section 34b is conical in configuration with the cross-sectional diameter of the bore adjacent section 34a least or smallest in diameter. Additionally, the member 34 is provided at one end with three bayonet type slots 34d, 34e and 34 seen best in FIG. 2, to receive the radial projections of pressure plate 40. In the figures only two of these projections are visible and these are indicated by the numerals 40a and 40b.

The remaining parts of the tap connector are connector cone 41, bearing washer 42, pressure screws 43, cap 44 held in position by hose clamp 45, and grommet 46 held in position by hose clamp 47. It is noted that the coating 38 extends beyond body member 34 to provide a receptacle for grommet 46 and that the cap 44 and coating 38 are formed with ridges 48 and 49, respectively, to define respective positions for clamps 45 and 47.

Connector cone 41 is formed of an electrically conducting material and provided with a full length longitudinal slot 41a. The connector cone 41 is provided, as will be explained in greater detail below, to encircle and grip the strands 50 of a cable 51 attached to the connector and the cone 41 is sized to the conductor to provide optimum en- .circlement and strand-to-strand contact. The slot 41a is provided to allow the connecting cone to become reduced in diameter in the fully assembled connector and firmly grip the cable strands. The internal surface of the cone is preferably provided with a corrugated configuration to aid in the provision of a firm contact with the conductor strands. The pressure plate 40, bearing washer 42 and screws 43 can be formed of any suitable conducting or non-conducting material having the strength to perform the function for which it is designed. The pressure plate 40 is provided to be received and held by its radial projections within the bayonet slots of body member 34 and to support the screws 43 therein. A tightening of the screws 43 will result in the screw ends embracing and abutting bearing washer 42 since tightening the screws will cause them to move downwardly as seen in FIG. 1 forcing the bearing washer 42 against cone 41 and driving the cone further within the conical bore 34b formed in body member 34. The conical cone 41 being driven deeper into the coni-' cal bore 34b results in the outer surface of cone 41 being forced inwardly radially due to hearing action and embracing strands 50 of the cable 51.

The cap 44 and grommet 46 can be formed of any suitable non-conducting material and the clamps 45 and 47 are formed of material such as will enable them to be tightened resulting in a tightening of the cap about body member 34 and the insulation 38 about grommet 46. As is known in the art it is necessary that the hose clamps be formed of material having suitable strength and resiliency for this purpose.

In assembling or in attaching a cable to the tap, the cable is prepared by skinning the insulation in the usual manner to expose stranded portion 50. The cable end is threaded through the grommet 46 and body member 34 until the exposed end 50 of the cable is inserted within connector cone 41.

The bearing washer 42, pressure plate 40 and screws 43 are then inserted with the screws 43 tightened to form a tight connection between the cone 41 and cable end portion 50. Cap 44 is then applied with clamp 45 which is tightened and clamp 47 tightened as well.

It is noted therefore that the cable can be connected to the assembly by mechanical tightening with a standard screwdriver to provide a permanent yet easily disconnected connection. Sealing is provided on either side for the cable by the grommet and cover and their respective clamps. Further, sealing is provided on either side of the transformer cover and throughout the connection since the insulation 38 covers most of the exposed members.

It is anticipated that the body member will be placed in position with insulation 38 surrounding it and that the line man will be provided with a kit which would include grommet 46, hose clamp 47, cone 41, hearing washer 42, pressure plate 40, cover 44 and hose clamp 45. The line man then, in fastening a cable to the assembly, would utilize the parts from the kit in the manner described above.

We claim:

1. A conductor connecting member including in combination a body member formed of an electrically con ductive material, a bore of said body member, an insulat-.

ing coating of said body member, a conical section of said bore, a collapsible connecting member having an receiving section of said bore adjacent the greater diameter end of said conical section, pressure plate means within said pressure plate receiving section and abutting said connecting member for urging said connecting member toward said conductor receiving section with said connecting member being collapsed about said conductor by the wedging action of its outer surface and the surface of the bore of said conical section, and first and second sealing means respectively providing a seal at the entrance to said pressure plate receiving section and at the entrance of said conductor receiving section.

2. A conductor connecting member in accordance with claim 1 in which said pressure plate means consists of a pressure plate supported within said pressure plate receiving section in a substantially fixed position, a bearing washer within said pressure plate receiving section between said pressure plate and said connecting member with an abutting portion thereof abutting said connecting member, and pressure applying means supported by said pressure plate and adjustable for applying determined force urging said bearing washer against said connecting member.

3. A conductor connecting member in accordance with claim 2 in which the pressure applying means are a plurality of screw members threadedly supported by said I claim 2 in which said pressure plate is provided with radial projections and the surface of said pressure receiving section is provided with bayonet slots to receive said projections by longitudinal insertion of said pressure plate and rotational locking thereof.

5. A conductor connecting member in accordance with claim 1 in which said first sealing means consists of a cap covering the entrance to said pressure plate receiving section and provided with a depending circular skirt and a clamp means for embracingly urging said skirt against insulating coating surrounding the entrance to said pressure plate receiving section.

'6. A conductor connecting member in accordance with claim 1 in which said second sealing means including a cylindrical extension of said insulating coating beyond the entrance to said conductor receiving section, a resilient grommet within said extension through which said conductor passes and a clamp means for embracingly urging said extension against said grommet and said grommet against said conductor.

References Cited UNITED STATES PATENTS 1,867,043 7/1932 Wirschitz 24126.3 2,493,556 1/1950 Stone 24136.3 X 3,414,868 12/1968 Howe 339116 3,444,505 5/ 1969 Becker 339270 X ERNEST R. PURSER, Primary Examiner US. Cl. X.R. 24l26; 339-270 

